This application is a continuation-in-part of application Ser. No. 505,930, filed June 20, 1983, which in turn is a continuation-in-part of application Ser. No. 168,449, filed July 10, 1980, now abandoned.
The present invention relates to automotive vehicle suspension systems, and in particular to improved suspension systems having resilient spacers between adjacent convolutions of coil springs, which enable the vehicle to ride smoothly in a designed manner on its suspension under normal driving conditions, but progressively stiffen the springs under severe driving conditions for enhanced handling.
Conventional automobiles have coil springs at the front two and possibly all four wheels for supporting the vehicle body and frame on the chassis. The springs isolate the body and frame from roadway shocks and undulations encountered by the wheels, so that occupants of the vehicle may ride in comfort, and shock absorbers dampen oscillations of the body on the springs. Ordinarily, the coil springs have a stiffness or compressibility which is a compromise between a smooth ride and good vehicle handling. Soft springs afford a cushioned ride and maximum passenger comfort on smooth or slightly undulating roadways. However, springs which are too soft do not offer sufficient resistance to acceleration squat or braking dive, or to collapse and possible bottoming under heavy vehicle loads or in response to pronounced roadway undulations or sharp turns at increased speeds, with the result that the vehicle body dips and leans excessively and vehicle handling, roadability and safety are compromised. Stiff springs, on the other hand, maintain the vehicle body and frame relatively steady and level for increased load carrying capability, roadability and handling under severe conditions, but do not satisfactorily isolate the body from roadway shocks and undulations, so that even on relatively smooth roads a rough ride may be experienced by passengers.
Unless a special suspension system is ordered and installed, automobiles most often are equipped with springs which compromise toward a soft ride. Consequently, their suspension systems are satisfactory under relatively smooth driving conditions as are usually encountered the majority of the time, but unsatisfactory and possibly dangerous under severe roadway or handling conditions or when the vehicle is heavily loaded.
Previous efforts to improve suspension systems of softly sprung automobiles have heretofore proven generally unsatisfactory. First, most modifications are expensive and difficult to implement and, secondly, they usually provide good roadability and handling only at the expense of passenger comfort. An obvious way to modify a vehicle's suspension system for improved handling and load carrying capability is to replace the original springs with heavy duty or relatively stiff springs. However, not only is spring replacement expensive, but stiff springs result in an uncomfortably hard ride under average driving conditions when the vehicle is less than heavily loaded. A somewhat less expensive approach is to replace the original shock absorbers with those of the load leveler type, which include separate coil springs for augmenting the vehicle springs, but this technique usually raises the vehicle body and results in a hard ride under average driving conditions. Alternatively, air pressurized shock absorbers may be used, but the pressure of the air must be continuously accommodated to changing vehicle loading and roadway conditions to maintain satisfactory handling.
Perhaps the least expensive known approach to stiffen a vehicle's suspension system is to insert rigid or metal spacers between adjacent convolutions of the coil springs. Such spacers at all times engage and usually expand the adjacent convolutions, and absolutely prevent any movement together of the same during compression of the remainder of the spring. Although the technique is often favored because of its economy of implementation, the resulting ridability of the vehicle under average driving conditions is harsh.